Automatic regulator suitable for furnace control



Feb. 7, 1939. w. c. NURSE 2,146,087

AUTOMATIC REGULATOR SUTTABLF. FOR FIZIRNACF) CONTROL Filed Sept. 12,1935

INVENTOR.

Patented Feb. 7, '1939 PATENT OFFICE AUTOMATIC REGULATOR SUITABLE- FOR v FURNACE CONTROL Weir C. Nurse, Omaha,'Nebr.

lApplication 'September 3 Claims.

This invention relatesto automatic regulators suitable for furnace control, and is herein illustrated as embodied in a thermostatic regulator for a hot air'furnace. A

Many forms of 'thermostatic regulators have been devised, and some of these may operate satisfactorily, but the devices are often complex, difficult to erect and adjust, and seldom work- Aing satisfactorily unless installed by expert workmen familiar with the special problems involved. Many devices depend upon closing electrical contacts which fail to work when dirty, and fail to work when the current is drawn from exhausted electrical batteries, and, moreover, can only be adjusted t on or off positions.

Other devices may be simpler, butlack the desired adjustment for various temperatures or can be adjusted at only a limited number of points, or lack the possibility of remote control. Still others require tobe installed by expert workmen when applied to furnaces which are already installed.

According to the present invention these and vother difculties are overcome, and a device is 25r provided which is variably adjustable, at many points, capable of remote control, easily set up by a workman unskilled in the art, and rugged enough to withstand ordinary wear and tear.

Other features and advantages will hereinafter appear.

In the accompanying drawing,

V Figure 1 is a diagrammatic side View of the device applied to a hot air furnace.

Figure 2 is a top view of the thermal element and its mount.'

FigureS. is asectional sideview of the same, showing some connecting parts, taken on the line 3-3 of Figure 2.

Figure 4 is an enlarged view on the line 4-4 of Figure 3.

Figure 5 is a similar view on the line 5-5 of Figure 3.

Figure 6 is an end view on the line 6--6 of Figure 3.

Figure 7 is an end view on the line 'I-l of yFigure 3.

In the drawing a furnace I0 is shown as heating air entering by a duct, not shown, by means of a re in the fire box within the usual top doors 50 II, I2, so that the hot air in the bonnet I3, may

be conveyed by ducts, not shown, to rooms above theY house floor I4.

The re in the furnace IIJ is shown as adapted to be controlled by the usual bottom draft door 55 or damper I5 andthe usual hingeddraft check 12, 1935, serial No. 40,206

(c1. zas- 102) valve I3. The primary control is by the damper I5 which is shown as adapted to be automatically controlled, but the range of automatic control may be altered by a hand settable device 53 as described below.

For effectingthis automatic control the bonnet I3 of the furnace is shown as crossed by a thermal controlling element I'I, in the form of an iron tube or support I8 containing an aluminum bar or rod I9, the aluminum bar having a much greater coefiicient of thermal expansion than the iron.

The aluminum bar I9 lengthens on being heated and therefore allows a regulating lever 20, on which it is pivoted at 2l, to drop around' its iioating pivot 22, with the result that the chain 23 drops and lowers the bottom draft door I5 to close or partly close it.

To obtain greater throw of the lever 20 by the aluminum bar I9, the bar is formed as a compound bar, having one stretch 24 looped around a pillar or pin 25 riveted diametrically across the tube I8 with its two ends 255l and 21 bent sharply around to the opposite sides of openings 28 in an iron connector element 29, and riveted or headedl over into the openings 28. Thus the aluminum bar I9 forms a U around the pillar 25. The iron connector element 29 is shown as a bar which may slide on the bottom of the tube I8 and connects the aluminum stretch 24 to a second aluminum stretch 30 which also is U shaped, being pivoted at its U 2l, as mentioned above, and with its ends 3| and 32 bent sharply around, as seen at Figure 5, to pass through openings 33 in the connector element 29, above the bar I9 and far from the openings 28.

As is shown in Figures 2 and 3, the aluminum stretches 24 and 30 are each nearly the length of the tube I8, and overlap most of their lengths so that the effective length of the aluminum bar I9 is nearly double the length of the tube I8, thus increasing the throw of the regulating lever 20 in that proportion, minus, of course, any

- change in length of the iron connector element 29 in the opposite direction.

The pivot 22 of the regulating lever 29 is shown as the U bend 34 of a link 35 which passes through an opening 36 with beveled edges 31 in the lever. The link also is bent into a U 38 at its opposite end which is similarly pivoted in an opening 39 having beveled edges in an adjusting lever40, said adjusting lever 40 swinging on a pivot 4I formed as the eye in the turned over end of a threaded bolt 42. The threaded bolt 42 lies in the threaded center 43 of a milled edged cap 44, turning in the end of the tube I8 and held in place by lugs or pins (not shown) which project into a peripheral groove 45 on the cap within the tube I8.

With a stretch of a little over four feet four inches between the pin 25 and the pivot ZI, and with a connector element 29 which is almost four feet long it has been found possible to obtain suincient throw of a four and a quarterinch regulating lever 20, between centers, to operate the bottom damper I5 satisfactorily, and this also provides a range of thermal element operating temperatures from 70 F. to 390 F. in a throw of ve inches of a five and three-sixteenthinch adjusting lever 4U. Automatic control is attained by movement of the compound bar I9 acting through the regulating lever 2U and'chain 23 on the primary control damper I5. The ad-V justing lever 40 may be set at various positions to provide a higher or lower range of automatically controlled temperatures.

In the form shown' the adjusting lever 40 is adapted to be readjusted from more than one point, and the connections not only set the draft door i5 but also set the draft check valve I6. To this end the adjusting lever 451s shown as adapted to be variously set by a chain or cord 45 connected to the outer end 41 of the lever and depending from the block 48 of a pulley 49. The pulley 45 is adapted to be raised or lowered by the cord 50 whichsupports it and is shown as connected to the hinged check I5 at one end 5I and to an electric control motor at the other end 52. The cord 50 may be pulled up by rotating a control pulley 53 in an upper room above the floor I4. One point on the cord` 58 Vis attached at the periphery of the pulley 53. Suicient friction is provided in the pulley 53 to hold it at anysetting against the weight or pull of the cord 5U. Y

When the pulley 53 is rotated to turn to the right the point of the arrow on it, it lifts the check I5 by drawing on the cord 58 around its pulleys 54 and 55. At the same time the pulley 53 loosens the stretch of the cord 55 around the pulleys 55, 5'?, and 58, thus dropping the pulley 49 so that it drops the lever 48 and causes the 'lever 28 to drop and close or partly closethe draft door I5. Y

The foregoing connections have been found useful although the door I5 works in one way manually and differently automatically.

In the form shown, the chain 23 is not con-` nected directly to the lever 2E), but is connected to a long narrow link Vt5 passing through an opening 5I in the end of the lever 20 and having bights 62 and 63 lying on opposite sides ofthe lever 40 so ras to steady it.

2,146,087 v f s 'the' valve 'Ill'` of The tube I8 is slotted at 64 on top to pass the lever 20, and the metal cut out of the slot is turned up into a stop 65 to prevent the tube I 8 from slipping into the furnace bonnet I3. y

The tube I8 is also slotted on the bottom'at 66 to pass the lever 40, and the metalcut out of the slot 66 is turned down to form a second stop 61 to match the stop 65.

It will be seen that turning the milled head.Y

44 screws the eye pivot 4I in or out of the tube I8, thus adjusting the normal setting of the bottom door I5 at will.

In addition to operating the door I5, the chainVV 23 may be connected to the throttle lever 68 of the gas supply pipe 69 off'a gas red boiler, the motion to close the door I5 partly closes valve 70.

Having thus described certain embodiments of Ythe invention, what is claimed is:

1. In a temperaturecontrol, a thermally operated bar, a first lever to which said bar is pivoted, a second lever for adjusting the rst lever, a

connection being such that the floating link cn which both are pivotedaseccnd n fixed pivot for the `second lever, Va controlled member, a link connecting saidfirst lever to the controlled member and embracing the second lever to guide it but allowing it to swing in its plane. Y

2. In a temperaturecontrol, a thermally operated bar, a rst lever to which said barris pivoted, a second lever for adjusting the first lever, a oating link on which'both are pivoted, a bar carrying a second fixed pivot for the second lever, a controlled member, a link connecting said first lever to the controlled memberV and embracingV the second lever to guide it but allowing it to swing in its plane, a support, and a screw rotatable onl said support to adjust'said bar to set the temperature aty which the devicers effective.

3. In a temperature control, a pair of U-bars one above the other facingoppositely and overlapping through most of their length and ex panding thermally atone rate, a connector lying between them and fast to the legs of each U and expanding thermally at another rate, a support.: 4'5" on which the connector may rest, a xedmember on the support to hold'one U, an adjusting lever at the other end of the support, a pivot for the adjusting lever on the support, a regulating lever Y engaged by the other U, a ilcating link pivoted in both levers toform a fulcrum for the regu-Y lating lever, anda member operated by the regulating lever, a pulling device connected to each lever, and a link in thepulling device of one lever embracing the other lever.

. wEIR C'.NURsE. 

